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This study out of Johns Hopkins, showing that a blood test might be useful in predicting the rate of cognitive decline in Alzheimer's disease, is being widely covered in the press. Here are some thoughts on the new science and what it might mean.

First, as the authors admit, this is very early stage work that has not yet been properly validated. Second, if the research is eventually validated, that would be only the starting point for the long product development process prior to the day when a physicians might have a test they could use in practice. Third, predicting the rate of progression may have some benefits, but if those benefits cannot be cost justified, then such a test might never be developed by any commercial interest.

I generally write optimistically in this space about new technologies and scientific advances that portend better care in the Alzheimer's arena. In this case, I am surprised at the amount of mainstream coverage that has been afforded such an early stage study with (in my opinion) dubious clinical value.

On that note, I think there is a very interesting aspect to this research. Given the massive recent investments in clinical trials to test agents for treating Alzheimer's disease, having a better understanding of each subject's propensity for cognitive decline could be highly valuable.

In a typical clinical trial, we apply a treatment to one group and a placebo to another group, then we look for differences in pre-determined outcomes. In the future, if we could segment the research subjets into groups based on their expected rate of cognitive decline (slow, medium, and fast), as this new blood tests suggests is possible, then we might more clearly detect a treatment effect by comparing expected decline with actual decline.

In this regard, I think a blood test for predicting the rate of cognitive decline in Alzheimer's patients, if validated and commercialized, could play an important role in the effort to develop new solutions to the looming Alzheimer's epidemic.